1. Field of Use
This invention relates to making crosslinkable lacquers for rocket motor propellants, the lacquers containing nitrocellulose, one or more explosive nitrate ester plasticizers and a propellant binder prepolymer such as polyglycol adipate. This invention, more particularly, relates to making these nitrocellulose lacquers gel free in shorter times by less hazardous methods.
2. Prior Art
Nitrocellulose lacquers heretofore have been made by a process that includes dissolving the nitrocellulose in a mixture of nitroglycerin and butanetriol trinitrate. The mixture of these latter nitrate esters is separately prepared from mixtures of the individual nitrate esters with 2-nitrodiphenylamine. There are hazards, however, associated with handling of the 99/1 nitroglycerin and 2-nitrodiphenylamine mixture.
Another possible route in manufacturing of nitrocellulose is to start with a solution of nitroglycerin and polyglycol adipate. Butanetriol trinitrate, dissolved in methylene chloride, is then added to this solution. The nitrocellulose is added to this admixture and the resulting combination of ingredients sparged. However, dissolution of the nitrocellulose has proven to be very difficult using this procedure. In one case some undissolved nitrocellulose remained even after sparging for several weeks at 140.degree. F. Reduced manufacturing time is possible by adding acetone during processing of the lacquer, but this addition introduces hazards due to the flammable vapors of acetone.